1. The Field of the Invention
This invention relates to the field of raster based graphic generation and, more specifically, to the transmission of data from a random access memory associated with raster object data to a raster object data processing module.
2. The Relevant Art
Raster Image Processors generally consist of hardware and software that converts vector graphics into raster (bitmapped) images. These processors are used in page printers, phototypesetters, and electrostatic plotters. Raster image processing can be of considerable duration, especially when large images are being printed.
In the current state of the art, printer systems receive compressed data of some format from a host over a system bus, such as a PCI bus. The compressed data is stored in memory that resides on a circuit board between the host and the printer itself. Once the data has been received into memory, it is sent to a decompressor and from the decompressor, to the printer. The path from the host to the printer is known as a data pipeline.
When large print operations, or jobs, are sent through the data pipeline for printing, the delay in processing and printing the data can be substantial. This delay can be caused by a number of factors such as decompression schemes, data bottlenecks, printer speed and memory speed. Data bottlenecks occur when data is sitting idle in the pipeline waiting to be transmitted to the next stage in the pipeline. While the data is idle, precious processing time is being wasted.
Often, in current art printing systems, different data types are assigned specific buses upon which they may be transmitted. For instance, a typical print job may contain JPEG image data, Linework image data, and Linework control data, with each data type being transmitted over its own, individual bus to the correct processor. Often, when one data type dominates a print job, the bus for that data type operates at 90–100 percent capacity, while the other two buses in the system run at perhaps 10% capacity. Due to the large amount of data being transmitted on a single bus, the data type that is transmitted on that bus begins to stack up in the pipeline and causes a data bottleneck. The bottleneck, in turn, slows down the operation of the printer or other raster image processing device.
From the above discussion, it can be seen that it would be beneficial to improve the performance of printing systems by providing a system and method for data transmission that is capable of utilizing all the available bus space in a print system to transmit print data more quickly to a high capacity print engine.